Variable-range hopping conductivity in Lu-doped Bi2Te3 |
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| Institution: | 1. Belgorod State University, Belgorod, 394015, Federation, Russia;2. Belgorod State Technological University Named After V.G. Shukhov, Belgorod, 308012, Federation, Russia;1. Belgorod State University, Belgorod, 308015, Russian Federation;2. Belgorod State Technological University named after V.G. Shukhov, Belgorod, 308012, Russian Federation;1. Centro de Estudios de Semiconductores, Facultad de Ciencias, Universidad de Los Andes, Mérida, 5101, Venezuela;2. Laboratory of Condensed Matter and Nanostructures (LMCN), Cadi-Ayyad University, Faculty of Sciences and Technology, Department of Applied Physics, Marrakech, Morocco;3. Laboratorio de Estructura e Ingeniería de Materiales Nanoestructurados (LEIMN), Centro de Investigación y Tecnología de Materiales (CITeMa), InstitutoVenezolano de Investigaciones Científicas (IVIC), Maracaibo, 4011, Venezuela;4. Laboratoire National des Champs Magnétiques Intenses, LNCMI-EMFL, CNRS/INSA/UGA/UPS, Toulouse & Grenoble, France;1. Institute of Physics, Czech Academy of Sciences, Na Slovance 2, Prague 8, Czech Republic;1. Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India;2. UGC-DAE Consortium for Scientific Research, Indore, Madhya Pradesh, 452001, India;3. Department of Physics, Banaras Hindu University, Varanasi,221005, India;4. Raja-Ramanna center for advanced technology, Indore, Madhya Pradesh, 452001, India |
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| Abstract: | The Seebeck coefficient enhancement due to an increase of density-of-states effective mass of electron has been found in n-type Bi1.9Lu0.1Te3. This enhancement is assumed to be related to forming the narrow and non-parabolic impurity (Lu) band with local maximum of electronic density of states lying near the Fermi level. Minimum in the specific electrical resistivity, ρ, originated from change of conductivity mechanism was observed at temperature Tm ≈ 11 K. Above Tm, the ρ change is due to decrease of electron mobility via acoustic phonon scattering. Below Tm, the variable-range hopping conductivity takes place. The electron hops between the localized states of the impurity energy band occur via tunneling process. Using the temperature and magnetic field dependences of ρ, the localization radius of electron was estimated as ≈6 nm. Two parts in the magnetic field dependence of the electrical resistivity were found at temperature of 2 K. At weak magnetic fields, the ρ change is in agreement with the variable-range hopping conductivity mechanism. At high magnetic fields, the positive and almost linear transverse and longitudinal magnetoresistances were observed at low temperatures. Both variable-range hopping conductivity and positive linear magnetoresistance are characteristics of disordered and inhomogeneous semiconductors. |
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| Keywords: | Impurity band Conductivity mechanism Variable-range hopping conductivity Magnetoresistance |
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